"""
1 313 4-1 2*1-1
2 232 4-2
3 151 4-3
4 070 4-4
"""
# hang = int(input("请输入行数："))
# for i in range(hang):
#     # print(i)
#     s = hang - i - 1
#     j = i*2+1
#     print(" "*s+"*"*j)
# a = [1, 2, 3]
# b = a
# b[0] = 99
# print(a)
s = {1, 2, 3}
s.add(4)
s.add(2)
print(s)
